Continuous advancements in virtualization and multi-processor core technology have given rise to the possibility of networking virtual machines on the same platform or physical device. The plurality of virtual machines may appear to each other and to other computing devices as distinct computing systems, each having its own Internet Protocol (IP) address. The virtual machines of a computing device may also share the IP address of the computing device, with each virtual machine using the same, real IP address. Sharing the IP address between multiple virtual machines, however, often requires the plurality of virtual machines to share a pool of ephemeral ports associated with the IP address. Ephemeral ports are assigned on an as needed basis to applications communicating across a network with another system or application. To receive return traffic, an application is assigned an ephemeral port. Multiple virtual machines, not aware of the other virtual machines sharing the computing device, may both allocate the same ephemeral port or ports of the computing device. Further, since the ephemeral ports are associated with the computing device and not any particular virtual machine, routing software of the computing device receiving the return traffic may not know to which virtual machine to route the traffic.